#!/bin/sh
set -e

# Carbon Web Server - Docker Entrypoint Script
# This script handles configuration and startup of the Carbon server

CONFIG_FILE="/app/server.conf"

# Helper: normalize boolean env vars (true/false/yes/no/1/0 -> true/false)
normalize_bool() {
    case "$(echo "$1" | tr '[:upper:]' '[:lower:]')" in
        true|yes|on|1) echo "true" ;;
        *) echo "false" ;;
    esac
}

# Normalize environment variables
USE_HTTPS=$(normalize_bool "${USE_HTTPS:-false}")
ENABLE_HTTP2=$(normalize_bool "${ENABLE_HTTP2:-false}")
ENABLE_WEBSOCKET=$(normalize_bool "${ENABLE_WEBSOCKET:-false}")

# Validate configuration constraints
validate_config() {
    # HTTP/2 requires HTTPS
    if [ "$ENABLE_HTTP2" = "true" ] && [ "$USE_HTTPS" != "true" ]; then
        echo "ERROR: HTTP/2 requires HTTPS to be enabled"
        echo "Set USE_HTTPS=true or disable HTTP/2 with ENABLE_HTTP2=false"
        exit 1
    fi
}

# Generate server.conf from environment variables
generate_config() {
    # Skip generation if user mounted a custom config and KEEP_CONFIG is set
    if [ -f "$CONFIG_FILE" ] && [ "${KEEP_CONFIG:-false}" = "true" ]; then
        echo "Using existing server.conf (KEEP_CONFIG=true)"
        return 0
    fi

    echo "Generating server.conf from environment variables..."
    cat > "$CONFIG_FILE" << EOF
# Carbon Web Server Configuration (Auto-generated)
# Generated at: $(date -u +"%Y-%m-%d %H:%M:%S UTC")

running = true

# Network configuration
port = ${PORT:-8080}
use_https = ${USE_HTTPS}
enable_http2 = ${ENABLE_HTTP2}
enable_websocket = ${ENABLE_WEBSOCKET}
server_name = ${SERVER_NAME:-0.0.0.0}

# Performance configuration
max_threads = ${MAX_THREADS:-4}
max_connections = ${MAX_CONNECTIONS:-1024}

# Logging configuration
log_file = /app/log/server.log
log_mode = ${LOG_MODE:-classic}

# Path configuration
www_path = /app/www

# SSL configuration (if HTTPS enabled)
ssl_cert_path = ${SSL_CERT_PATH:-/app/ssl/cert/cert.pem}
ssl_key_path = ${SSL_KEY_PATH:-/app/ssl/key/key.key}
EOF

    if [ $? -ne 0 ]; then
        echo "ERROR: Failed to write configuration file"
        exit 1
    fi
}

# Validate SSL certificates if HTTPS is enabled
validate_ssl() {
    if [ "$USE_HTTPS" = "true" ]; then
        CERT_PATH="${SSL_CERT_PATH:-/app/ssl/cert/cert.pem}"
        KEY_PATH="${SSL_KEY_PATH:-/app/ssl/key/key.key}"

        if [ ! -f "$CERT_PATH" ]; then
            echo "ERROR: SSL certificate not found at $CERT_PATH"
            echo "Please mount your SSL certificate or set SSL_CERT_PATH"
            exit 1
        fi

        if [ ! -r "$CERT_PATH" ]; then
            echo "ERROR: SSL certificate at $CERT_PATH is not readable"
            exit 1
        fi

        if [ ! -f "$KEY_PATH" ]; then
            echo "ERROR: SSL key not found at $KEY_PATH"
            echo "Please mount your SSL key or set SSL_KEY_PATH"
            exit 1
        fi

        if [ ! -r "$KEY_PATH" ]; then
            echo "ERROR: SSL key at $KEY_PATH is not readable"
            exit 1
        fi

        echo "SSL certificates validated successfully"
    fi
}

# Create necessary directories
setup_directories() {
    mkdir -p /app/log 2>/dev/null || true
    mkdir -p /app/www 2>/dev/null || true
}

# Print startup banner
print_banner() {
    echo "========================================"
    echo " Carbon Web Server"
    echo "========================================"
    echo " Port:       ${PORT:-8080}"
    echo " HTTPS:      ${USE_HTTPS}"
    echo " HTTP/2:     ${ENABLE_HTTP2}"
    echo " WebSocket:  ${ENABLE_WEBSOCKET}"
    echo " Log Mode:   ${LOG_MODE:-classic}"
    echo "========================================"
}

# Main entry point
main() {
    setup_directories
    validate_config
    generate_config
    validate_ssl
    print_banner

    # Verify server binary exists and is executable
    if [ ! -x /app/server ]; then
        echo "ERROR: Server binary not found or not executable at /app/server"
        exit 1
    fi

    echo "Starting Carbon server..."

    # Execute the server (replaces shell process)
    exec /app/server
}

main "$@"